There are heaps of Toys to buy worth only 100 Sparks in the Horseplay Toys section, buying all of these will give you plenty of progress towards this Achievement.
Be sure to look through the other section for Toys at this price.
If you purchase each one of these toys, the next lowest price is 250 Sparks, and there is an abundance of toys at this Price. Just keep gather sparks and buying until you get this.